<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>浮动清除</title>
  <style>
    .box{
      width: 150px;
      height: 150px;
      border: 1px solid;
      margin-left: 10px;

    }


     .left{
         float: left;
     }


     .clearfix {


         /*left right both*/
          clear: both;
     }

  </style>
</head>
<body>


  <div class="box left">
        box-1
  </div>

<div class="clearfix">
    hello
</div>

</body>
</html>